Create a program to input the length and width of a rectangle
and calculate and print the perimeter and area of the rectangle. To
do this you will need to write a Rectangle class and a separate
runner class. Your program should include instance variables,
constructors, an area method, a perimeter method, a toString
method, accessor and mutator methods, and user input. Your runner
class should include 3 Rectangle objects. One default rectangle,
one coded rectangle, and one user input...